A Mobile County grand jury has indicted Mary G. Montgomery High School math teacher Alicia Gray on charges of first-degree sodomy, sexual abuse and being a school employee who engaged in a sex act with a student younger than 19.

The most serious charge, sodomy, is a Class A felony punishable by 10 years to life in prison. The other felony charge is punishable by two to 20 years in prison, and the sexual abuse charge is a misdemeanor.

The charges are not a surprise; the Mobile County Sheriff’s Office had arrested Gray on those allegations in February. The timing, though, is a bit surprising, since a judge had just found probable cause last week to send the case to a grand jury.

“We had a sitting grand jury, and we just went ahead and presented it to the grand jury,” said Mobile County Assistant District Attorney Nicki Patterson, who prosecutes child sex abuse cases.

Christine Hernandez, an attorney who represents Gray, said she had seen the charging documents.

“Until I actually see the indictment, I really can’t comment,” she said.

Often, it takes months for a grand jury to act on a case once a district court judge has forwarded the charges. In this case, Patterson said, law enforcement investigators had enough information to proceed.

“We would not have authorized an arrest if the investigation was not complete,” she said.

Gray, 28, remains free on bail and on paid leave from the Mobile County school system.

Citing an affidavit that since has been sealed, NBC-15 reported that the 14-year-old student told investigators that the relationship began around New Year’s Day and intensified, ultimately leading to oral sex near the student’s home.

Patterson would not discuss the evidence in detail but added that it consisted of more than simply the student’s word.

“There is some additional evidence to support his statement,” she said.

Patterson also suggested that prosecutors expect the full cooperation of the student, which sometimes is an issue in cases in which teenagers have been willing participants in sexual relationships with adults. Under the law, minors cannot consent to sex.

“He has testified when call upon to do so,” she said.

The case now will be assigned randomly to a Mobile County Circuit Court judge, who will set an arraignment date. That likely will be in a few weeks.